Because by many accounts he is an absolute defensive tire fire who needs to be carefully sheltered so that he doesn't cause more problems than he solves.
To use a name someone above invoked, he's like a better version of Ryan Merkley.
Though honestly that might be part of the plan. Make a good looking reclamation project trade for a guy who could become an offensive stalwart on the back end. And if he happens to torpedo the team's defensive ability for a year or two while they force-feed him decent minutes and it costs the team wins, then aww shucks isn't that just the worst luck